Foil printing

ABSTRACT

A method for producing a printed image having a region that is foil printed comprising: printing at least one region of the image with a toner; printing the region of the image to be foil printed with a foiling adhesive that sticks to a foil on a printing foil, which adhesive has a melting temperature lower than the melting temperature of the toner, and pressing the printing foil to the image and heating the printing foil to a temperature greater than the melting temperature of the foiling adhesive and less than the melting temperature of the toner.

RELATED APPLICATIONS

The present application is a U.S. national application ofPCT/IL00/00018, filed Jan. 9, 2000.

FIELD OF THE INVENTION

The invention relates to foil printing and in particular to transferringfoil color from a foil and adhering the color to portions of an image.

BACKGROUND OF THE INVENTION

In foil printing, a colored foil bonded to a backing, hereinafterreferred to as a “foil backing” is transferred from the foil backing toa substrate to form an image or parts of an image on the substrate.Hereinafter, the colored foil and its foil backing are referred to as a“printing foil”. In foil printing on paper, generally, the paper isprinted with a desired image using a conventional printing press andconventional printing inks. The image is then printed with an adhesive,hereinafter referred to as a “foiling adhesive”, in those areas of theimage to which it is desired to transfer the foil. The foiling adhesiveis usually a dry toner “printed” in a xerographic process, in which thetoner is bonded to the paper by fusing. A printing foil having a desiredcolor foil is then pressed to the paper and heated. The heating causesthe printed toner to melt and become tacky. The printing inks on theother hand are substantially unaffected by the heat and pressure. Thefoil sticks to the tacky toner but not the printed inks. When theprinting foil is removed, foil detaches from the foil backing andadheres to the foiling adhesive to cover the areas of the image that itis desired to foil print. Foils are generally metallic and are oftenused for special printing effects, such as for example, to print goldand purple metallic color details on feathers of an image of a peacockor to gild a name on a business card.

When foil printing an image, the transfer of a foil to only desiredareas of the image requires that areas of the image that are not to befoil printed not stick to the foil when the printing foil bearing thefoil is pressed to the image and heated. In many printing processes animage is printed on paper by depositing toners of appropriate colors onthe paper and fusing the toners to the paper. Toners used to print animage are fused to paper similarly to the way that toner used as afoiling adhesive in a conventional foil printing process is bonded to aprinted image. If a printing foil is pressed to an image printed withtoners and heated, the toner melts and foil adheres to all printed areasof the image that contact the printing foil. When an image is printedwith toners it is therefore not practical to foil print only parts ofthe image using conventional foil printing processes. It is certainlynot practical to foil print only fine details of such an image, such asfor example details of the feathers of the peacock image noted above.

SUMMARY OF THE INVENTION

An aspect of some preferred embodiments of the present invention relatesto providing a method for foil printing selected areas of an imageprinted with toners.

An aspect of some preferred embodiments of the present invention relatesto providing a foiling adhesive for foil printing the image that has amelting temperature that is less than the melting temperature of thetoners used to print the image.

To foil print an image printed with the toners the foiling adhesive isprinted on those areas of the image to which it is desired to apply afoil. A printing foil is pressed to the image and heated to atemperature that is above the melting temperature of the foilingadhesive and below the melting temperature of the toners. The foilingadhesive becomes tacky and sticks to the foil. The toners do not becometacky and do not stick to the foil because the temperature to which theprinting foil is heated is below the melting temperature of the toners.When the printing foil is removed from the image, after cooling, foil isleft only on those areas of the image printed with the foiling adhesive.

An aspect of some preferred embodiments of the present invention relatesto providing a printing foil having its foil covered with a protective“non stick” layer that retards adhesion of the foil to the toners butnot to the foiling adhesive when the printing foil is pressed to theimage and heated.

In a preferred embodiment of the present invention, the foiling adhesivehas a higher melting temperature than the toners used to print theimage. When the printing foil is pressed to the image and heated to atemperature above the melting temperature of the adhesive its foilsticks to the adhesive but not to the toners. During heating of theprinting foil, heat from the foil softens the toners. Preferably, thetoners are highly viscous at the melting temperature of the adhesive sothat the toners do not flow during the foil printing process.

There is therefore provided in accordance with a preferred embodiment ofthe present invention a method for producing a printed image having aregion that is foil printed comprising: printing at least one region ofthe image with a toner; printing the region of the image to be foilprinted with a foiling adhesive that sticks to a foil on a printingfoil, which adhesive has a melting temperature lower than the meltingtemperature of the toner; and pressing the printing foil to the imageand heating the printing foil to a temperature greater than the meltingtemperature of the foiling adhesive and less than the meltingtemperature of the toner.

Preferably, the toner comprises a material from the group of materialsconsisting of ethylene methacrylic acid copolymer and ionomers ofethylene methacrylic acid copolymer. In some preferred embodiments ofthe present invention the toner comprises ethylene methacrylic acidcopolymer. In some preferred embodiments of the present invention thetoner comprises an ionomer of ethylene methacrylic acid copolymer.

Alternatively or additionally the adhesive comprises a material chosenfrom the group of materials consisting of: ethylene acrylic ester maleicanhydride terpolymer; low molecular weight ethylene acrylic acidcopolymer; ionomers of low molecular weight ethylene acrylic acidcopolymer; and esters of ethylene acrylic acid copolymer.

In some preferred embodiments of the present invention the adhesivecomprises ethylene acrylic ester maleic anhydride terpolymer. In somepreferred embodiments of the present invention the adhesive compriseslow molecular weight ethylene acrylic acid copolymer. In some preferredembodiments of the present invention the adhesive comprises an ionomerof low molecular weight ethylene acrylic acid copolymer. In somepreferred embodiments of the present invention the adhesive comprises anester of ethylene acrylic acid copolymer.

There is further provided in accordance with a preferred embodiment ofthe present invention a method for producing a printed image having aregion that is foil printed comprising: printing at least one region ofthe image with a toner; printing the region of the image to be foilprinted with a foiling adhesive; covering a foil side of a printing foilwith a layer of material that sticks to melted foiling adhesive but notto the toner; and pressing the printing foil to the image and heatingthe printing foil to a temperature greater than a tacking temperature ofthe foiling adhesive.

Preferably the layer of material that doesn't stick to toner comprises amaterial chosen from the group of materials consisting of: methacryliccopolymer resin; polyester; polyvinyl chloride; and polycarbonate.

In some preferred embodiments of the present invention the non-sticklayer comprises methacrylic copolymer resin. In some preferredembodiments of the present invention the non-stick layer comprisespolyester. In some preferred embodiments of the present invention thenon-stick layer comprises polyvinyl chloride. In some preferredembodiments of the present invention the non-stick layer comprisespolycarbonate.

Additionally or alternatively the toner comprises a material chosen fromthe group of materials consisting of: ethylene methacrylic acidcopolymer and ionomers of ethylene methacrylic acid copolymer; lowmolecular weight ethylene acrylic acid copolymer and ionomers of lowmolecular weight ethylene acrylic acid copolymer, esters of ethylenemethacrylic acid; and esters of ethylene acrylic acid.

In some preferred embodiments of the present invention the tonercomprises ethylene methacrylic acid copolymer. In some preferredembodiments of the present invention the toner comprises ionomer ofethylene methacrylic acid copolymer. In some preferred embodiments ofthe present invention the toner comprises low molecular weight ethyleneacrylic acid copolymer. In some preferred embodiments of the presentinvention the toner comprises an ionomer of a low molecular weightethylene acrylic acid copolymer. In some preferred embodiments of thepresent invention the toner comprises an ester of ethylene methacrylicacid. In some preferred embodiments of the present invention the tonercomprises an ester of ethylene acrylic acid.

Additionally or alternatively, the adhesive comprises a material chosenfrom the group of materials consisting of styrene acrylic acidcopolymer; polyamide; ethylene acrylic ester maleic anhydrideterpolymer. In some preferred embodiments of the present invention theadhesive comprises styrene acrylic acid copolymer. In some preferredembodiments of the present invention the adhesive comprises polyamide.In some preferred embodiments of the present invention the adhesivecomprises ethylene acrylic ester maleic anhydride terpolymer.

There is further provided in accordance with a preferred embodiment ofthe present invention a printing foil for foil printing a region of animage comprising: a substrate; a layer of foil bonded to the substrate;and a layer covering the foil formed from a material chosen from thegroup of materials consisting of methacrylic copolymer resin, polyester,polycarbonate and polyvinyl chloride.

In some preferred embodiments of the present invention the layercovering the foil comprises methacrylic copolymer resin. In somepreferred embodiments of the present invention the layer covering thefoil comprises a polyester. In some preferred embodiments of the presentinvention the layer covering the foil comprises polycarbonate. In somepreferred embodiments of the present invention the layer covering thefoil comprises polyvinyl chloride.

BRIEF DESCRIPTION OF FIGURES

The invention will be more clearly understood from the followingdescription of preferred embodiments thereof read with reference tofigures attached hereto. In the figures, identical structures, elementsor parts that appear in more than one figure are generally labeled withthe same numeral in all the figures in which they appear. Dimensions ofcomponents and features shown in the figures are chosen for convenienceand clarity of presentation and are not necessarily shown to scale. Thefigures are listed below.

FIG. 1 shows a schematic image of a parrot printed using toners that isto have its wings and tail feathers foil printed with an iridescentgreen metallic color, in accordance with a preferred embodiment of thepresent invention;

FIG. 2 schematically shows the parrot shown in FIG. 1 after foilprinting in accordance with a preferred embodiment of the presentinvention;

FIGS. 3A and 3B show schematically in cross section view foil printingthe parrot shown in FIGS. 1 and 2, in accordance with a preferredembodiment of the present invention; and

FIGS. 4A and 4B show schematically in cross section view foil printingthe parrot shown in FIGS. 1 and 2, in accordance with another preferredembodiment of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 schematically shows an image of a parrot 20 printed on paper 22with toners that is to be foil printed in accordance with a preferredembodiment of the present invention. The image of parrot 20 ispartitioned into various bounded color regions 24. A letter in a boundedcolor region 24 represents a particular color toner with which theregion is printed. For example, the letters Y, R, B, O shown in FIG. 1might represent bright yellow, red, blue and orange toner respectively.The toners have a melting temperature T₁. A shoulder feather colorregion 26 and tail feather color regions 28, are to be foil printed withan iridescent metallic green and are printed, in a preferred embodimentof the invention, with a foiling adhesive which is represented by theletters AD, having a melting temperature T₂, which is less than T₁.

In a preferred embodiment of the present invention toners are liquidtoners such as those described in U.S. Pat. No. 5,407,771 to Landa etal. Preferably, the toners comprise ethylene methacrylic acid copolymermade by Du Pont and sold under the trade name Nucrel 699. Nucrel 699 hasa melting temperature T₁ between about 110° C.-120° C. Preferably thetoners are toners produced and sold by Indigo N. V. of the Netherlandsunder the trade names EI-Mark 3.0 and EI-Mark 3.1 Other toners suitablefor use with the present invention are based on: ethylene methacrylicacid low copolymers sold by Du Pont under the trade names NUCREL resins599 and 925 and their ionomers, sold by Du Pont under the trade nameSURLYN. Esters of these materials can also be used.

Preferably, a foiling adhesive used with these toners that has a meltingtemperature less than the toners comprises ethylene acrylic ester maleicanhydride terpolymer, manufactured by ELF Atochem and sold under thetrade name Lotader 8200. Lotader 8200 has a melting temperature T₂ ofabout 1000° C.

To prepare a quantity of the foiling adhesive, 1800 g of Isopar-L madeby Exxon and 1200 g of Lotader 8200 is loaded into a four gallon sizeRoss double planetary mixer that is preheated to about 140° C. Thestirring speed of the mixer is set to stirring speed 6 and the loadedmaterials are stirred for about 1.5 hours until the mixture reaches atemperature of about 118° C. When the mixture reaches about 118° C. thestirring speed is reduced to stirring speed 3 and the mixture is air fancooled for about three hours until the mixture temperature reaches about40° C. 1150 g of the mixture, 2.3 g of aluminum stearate (mfg. by Riedelde Haen) and 1147.7 g Isopar-L are then ground together at 250 rpm in a1S attritor (mfg. by Union Process) loaded with {fraction (3/16)}″carbon steel balls for about 26 hours at 40° C. The ground mixture isdispersed in a non-polar liquid such as an Isopar-L with a ratio byweight of mixture to dispersant of about 4% to provide the foilingadhesive.

Foiling adhesive can also be prepared, in accordance with a preferredembodiment of the present invention, using a procedure similar to thatdescribed above in which Lotader 8200 is replaced with Lotader 5500 orLotader 6200/5500. Adhesives suitable for use in the present inventioncan also be similarly produced using ethylene acrylic acid low molecularweight copolymers AC 540 and AC 5120 (Allied Signal) or their lowmolecular weight ionomers AC 293 or 295 (Allied Signal), ethylenemethacrylic acid (ester); and esters of ethylene acrylic acidcopolymers.

To foil print iridescent green on shoulder and tail feather regions 26and 28, a printing foil (not shown) having an iridescent green foil ispressed to the image of parrot 20 and heated to a temperature T₃, whichsatisfies the relationship T₂<T₃<T₁, using methods known in the art. Attemperature T₃, foiling adhesive AD printed in shoulder and tail featherregions 26 and 28 melts and sticks to the iridescent green color on theprinting foil. Toners, which having a melting temperature T₁>T₃, do notmelt and therefore do not stick to the iridescent green foil. When theprinting foil is removed from the image of parrot 20, the iridescentgreen color covers substantially only shoulder and tail feather regions26 and 28. FIG. 2 schematically shows the image of parrot 20 shown inFIG. 1 after foil printing, in accordance with a preferred embodiment ofthe present invention. The iridescent green is represented by shadingand covers only shoulder and tail feather regions 26 and 28.

FIG. 3A schematically shows a cross section 30 of a portion 32 of theimage of parrot 20 being foil printed with iridescent green using aprinting foil 34, in accordance with preferred embodiment of the presentinvention. The cross section is taken along a bold line 36 shown in FIG.2. Printing foil 34 preferably comprises a thin substrate 38 on which alayer 40 of iridescent green foil is deposited using methods known inthe art. A block arrow 44 schematically represents a pressure with whichprinting foil 34 is pressed to image portion 32. Printing foil 34 isheated to a temperature T₃ shown in parentheses besides the numeral 34.

Image portion 32 of parrot 20 comprises a region 46 of paper 20 on whichparrot 20 is printed, which is printed with toner B, and a region 48,which is printed with adhesive AD, in accordance with a preferredembodiment of the present invention. Toner B has a melting temperatureT₁ (which is greater than T₃) shown in parentheses besides numeral 46.Adhesive AD has a melting temperature T₂ (which is less than T₃) shownin parentheses besides numeral 48. FIG. 3B schematically shows printingfoil 34 partially removed from image portion 32 of parrot 20 followingtransfer of foil to image portion 32. A portion 40′ of foil layer 40that was pressed to foiling adhesive AD has separated from printing foilsubstrate 38 and is bonded to foiling adhesive AD. Substantially no foilis bonded to toner B, in accordance with a preferred embodiment of thepresent invention.

Parrot 20 can also be foil printed using a printing foil having its foilcovered with a nonstick layer that prevents adhesion of the foil to thetoners, in accordance with a preferred embodiment of the presentinvention, even if adhesive AD has a higher melting temperature than thetoners. Preferably, the foiling adhesive AD is applied to shoulderfeather color region 26 and tail feather color regions 28 in a dryxerography process. Preferably the adhesive is styrene acrylic acidcopolymer, which has a melting temperature of about 160° C. This may bein the form of a powder toner or a liquid toner. When in powder form,preferably the powder is a colorless powder prepared by methods known inthe art. Other adhesives suitable for use in the present invention canalso be formed using a polyamide or Lotader 5500, 6200/5500 or 8200 asdescribed above.

Preferably, a non-stick layer that adheres to the adhesive but retardsadhesion of a foil to the toners in the image is formed from one of thefamily of methacrylic copolymer resins made by Du Pont that are soldunder the trade names Elvacite 2014, 2016, 2043 and 2044. Non sticklayers in accordance with preferred embodiments of the present inventioncan also be formed using polyesters, polycarbonate and polyvinylchloride.

At a working temperature, preferably marginally greater than about 160°C. when for example styrene acrylic acid copolymer is used as anadhesive, to which a foil is heated to transfer foil to regions 26 and28, toners printed in color regions 24 melt. However, at the workingtemperature the toners are viscous and do not flow substantially duringthe time that foil is being transferred from the printing foil toshoulder feather region 26 and tail feather regions 28. As a result, theheat and pressure to which the image of the parrot is subjected duringthe foil printing process do not substantially degrade the quality ofthe image.

Toners printed in color regions 24 that may be used with the non-sticklayer, in accordance with a preferred embodiment of the presentinvention are toners based on Nucrel 699, such as Indigo N. V. tonersEI-Mark 3.0 and EI-Mark 3.1 referenced above. Other toners suitable foruse with the present invention are based on: ethylene methacrylic acidcopolymers (sold by Du Pont under the trade names NUCREL resins 599 and925) and their ionomers (sold by Du Pont under the trade name SURLYN);low molecular weight ethylene acrylic acid copolymers (trade names AC540and AC 5120 by Allied Signal Inc.) and their ionomers (trade names ACRYN293 and 295 by Allied Signal Inc); and esters of these materials.

FIGS. 4A and 4B schematically show a cross section view 50 of portion32, shown in FIGS. 3A and 3B, of the image of parrot 20 being foilprinted with iridescent green using a printing foil 52 comprising anon-stick layer, in accordance with preferred embodiment of the presentinvention. In FIGS. 4A and 4B, unlike in FIGS. 3A and 3B, foilingadhesive AD, which covers region 48 of portion 32, has a meltingtemperature T₂ that is greater than the melting temperature T₁ of tonerB, which covers region 46 of portion 32.

Printing foil 52 comprises a thin substrate 38 and a layer 40 ofiridescent green foil. Foil layer 40 is covered with a layer 42 ofnon-stick material that does not stick to the toners used to printparrot 20, in accordance with a preferred embodiment of the presentinvention. A block arrow 44 schematically represents a pressure withwhich printing foil 52 is pressed to image portion 32. Printing foil isheated to a temperature T₃ that is greater, preferably marginallygreater, than T₂. Temperatures T₁, T₂ and T₃ therefore satisfy therelationship T₁<T₂<T₃. At temperature T₃ toner B softens and melts butdoes not stick to non-stick layer 42. Furthermore, at temperature T₃,the viscosity of toner B is sufficiently high so that during the foilprinting process toner B does not flow substantially.

FIG. 4B schematically shows printing foil 52 partially removed fromportion 32 of parrot 20 following transfer of foil to image portion 32.A portion 42′ of non-stick layer 42 that was pressed to foiling adhesiveAD is bonded to adhesive AD and has “carried with it” a portion 40′ offoil layer 40, which has separated from printing foil substrate 38.Substantially no portion of non-stick layer 42 and therefore of foillayer 40 is bonded to toner B, in accordance with a preferred embodimentof the present invention.

In the description and claims of the present application, each of theverbs, “comprise” “include” and “have”, and conjugates thereof, are usedto indicate that the object or objects of the verb are not necessarily acomplete listing of members, components, elements or parts of thesubject or subjects of the verb.

The present invention has been described using detailed descriptions ofpreferred embodiments thereof that are provided by way of example andare not intended to limit the scope of the invention. The describedpreferred embodiments comprise different features, not all of which arerequired in all embodiments of the invention. Some embodiments of thepresent invention utilize only some of the features or possiblecombinations of the features. Variations of embodiments of the presentinvention that are described and embodiments of the present inventioncomprising different combinations of features noted in the describedembodiments will occur to persons of the art. The scope of the inventionis limited only by the following claims.

What is claimed is:
 1. A method for producing a printed image having aregion that is foil printed comprising: printing at least one region ofthe image with a toner; printing the region of the image to be foilprinted with a foiling adhesive that sticks to a foil on a printingfoil, which adhesive has a melting temperature lower than the meltingtemperature of the toner; and pressing the printing foil to the imageand heating the printing foil to a temperature greater than the meltingtemperature of the foiling adhesive and less than the meltingtemperature of the toner.
 2. A method according to claim 1 wherein thetoner comprises a material from the group of materials consisting ofethylene methacrylic acid copolymer and ionomers of ethylene methacrylicacid copolymer.
 3. A method according to claim 2 wherein the tonercomprises ethylene methacrylic acid copolymer.
 4. A method according toclaim 2 wherein the toner comprises an ionomer of ethylene methacrylicacid copolymer.
 5. A method according to claim 1 wherein the adhesivecomprises a material chosen from the group of materials consisting of:ethylene acrylic ester maleic anhydride terpolymer; low molecular weightethylene acrylic acid copolymer; ionomers of low molecular weightethylene acrylic acid copolymer; and esters of ethylene acrylic acidcopolymer.
 6. A method according to claim 5 wherein the adhesivecomprises ethylene acrylic ester maleic anhydride terpolymer.
 7. Amethod according to claim 5 wherein the adhesive comprises low molecularweight ethylene acrylic acid copolymer.
 8. A method according to claim 5wherein the adhesive comprises an ionomer of low molecular weightethylene acrylic acid copolymer.
 9. A method according to claim 5wherein the adhesive comprises an ester of ethylene acrylic acidcopolymer.
 10. A method for producing a printed image having a regionthat is foil printed comprising: printing at least one region of theimage with a toner; printing the region of the image to be foil printedwith a foiling adhesive; covering a foil side of a printing foil with alayer of material that sticks to melted foiling adhesive but not to thetoner; and pressing the printing foil to the image and heating theprinting foil to a temperature greater than a tacking temperature of thefoiling adhesive.
 11. A method according to claim 10 wherein the layerof material that doesn't stick to the toner comprises a material chosenfrom the group of materials consisting of: methacrylic copolymer resin;polyester; polyvinyl chloride; and polycarbonate.
 12. A method accordingto claim 11 wherein the non-stick layer comprises methacrylic copolymerresin.
 13. A method according to claim 11 wherein the non-stick layercomprises polyester.
 14. A method according to claim 11 wherein thenon-stick layer comprises polyvinyl chloride.
 15. A method according toclaim 11 wherein the non-stick layer comprises polycarbonate.
 16. Amethod according to claim 10 wherein the toner comprises a materialchosen from the group of materials consisting of: ethylene methacrylicacid copolymer and ionomers of ethylene methacrylic acid copolymer; lowmolecular weight ethylene acrylic acid copolymer and ionomers of lowmolecular weight ethylene acrylic acid copolymer; esters of ethylenemethacrylic acid; and esters of ethylene acrylic acid.
 17. A methodaccording to claim 16 wherein the toner comprises ethylene methacrylicacid copolymer.
 18. A method according to claim 16 wherein the tonercomprises an ionomer of ethylene methacrylic acid copolymer.
 19. Amethod according to claim 16 wherein the toner comprises low molecularweight ethylene acrylic acid copolymer.
 20. A method according to claim16 wherein the toner comprises an ionomer of low molecular weightethylene acrylic acid copolymer.
 21. A method according to claim 16wherein the toner comprises an ester of ethylene methacrylic acid.
 22. Amethod according to claim 16 wherein the toner comprises an ester ofethylene acrylic acid.
 23. A method according to claim 10 wherein theadhesive comprises a material chosen from the group of materialsconsisting of: styrene acrylic acid copolymer; polyamide; and ethyleneacrylic ester maleic anhydride terpolymer.
 24. A method according toclaim 23 wherein the adhesive comprises styrene acrylic acid copolymer.25. A method according to claim 23 wherein the adhesive comprisespolyamide.
 26. A method according to claim 23 wherein the adhesivecomprises ethylene acrylic ester maleic anhydride terpolymer.